1. Field of the Art
The present invention relates to a device for entering coordinate data for moving a cursor on the screen of a cathode-ray tube display for microcomputers, word processing instruments, and other data processing equipment.
2. Related Art Statement
In the art of moving a cursor in an X-Y coordinate system on the screen of a cathode-ray tube display or video terminal (hereinafter referred to as "CRT display"), there have been known cursor keys or buttons which are disposed on a data input keyboard. The cursor on the display screen is moved right and left along the X axis by X-axis cursor keys, and back and forth or up and down along the Y axis by Y-axis cursor keys. When it is desired to move the cursor from a first point on the screen to a second point whose X and Y coordinates are both different from the corresponding X and Y coordinates of the first point, the appropriate X-axis cursor key should be operated before the appropriate Y-axis cursor key is operated, or vice versa, so that the cursor is moved first along one axis and then along the other axis. In either case, movements of the cursor on the display screen along both X and Y axes require cumbersome operations of the cursor keys on the keyboard.
To free the operator from such cumbersome operations of the plural cursor keys, there is proposed a coordinate-data input device using a manually movable unit which is moved by the operator on a planar board, so that the cursor is moved on the CRT display screen, following paths of movements of the manually movable unit on the planar board, As the manually movable unit is moved, data on the amounts and directions of the movement are entered into a central processing unit of a computer, and the cursor is moved based on the data applied to the central processing unit. Consequently, the operator may easily move the cursor to a desired position on the display screen, by moving the manually movable unit on the planar board while observing the current position of the cursor on the screen.
According to the above-introduced coordinate-data input device, however, the distances of movement of the cursor on the screen are proportional to the amounts of movements of the manually operable unit on the planar board. That is, the ratio of the cursor movement to the movement of the manually movable unit is fixed. In the case where the planar board is limited in size, the movement of the manually movable unit must be repeated two or more times when the cursor is moved by a relatively large distance. In a coordinate-data input device of optical type wherein a planar board has a lattice made up of multiple intersecting X and Y scanning lines which are optically detected during movements of a manually movable unit on the lattice so that the cusor is moved based on the optical detection of the scanning lines, the size of the planar lattice board is limited, particularly when the lattice board is disposed on a keyboard or similar data input device. The limited size of the lattice board leads to increased number of operations of the manually movable unit.